/Engine/Source/Runtime/GeometryCore/Public/FrameTypes.h
Internally the representation is the same as an FTransform, except a Frame has no Scale.
template<typename RealType> struct TFrame3
TVector< RealTy...
Origin
Origin of the frame
TQuaternion< Re...
Rotation
Rotation of the frame. Think of this as the rotation of the unit X/Y/Z axes to the 3D frame axes.